Rinse the potatoes, half them, place them in a pot and cover then with cold water.
Bring to boil and cook the potatoes over medium heat until fork tender, but not too soft, about 10 - 15 minutes
Meanwhile, in a small bowl, whisk together the olive oil, lemon juice, salt and dijon mustard. Add the scallions, parsley and tarragon and stir.
When the potatoes are ready, drain them and place them in a large bowl. Pour the sauce over the hot potatoes and gently toss so that it is evenly distributed around the potatoes.
Can be served warm or cold.